If you regularely use the Snapshot feature of Xenserver, or, like us, run an external backup tool (Alike by Quorumsoft) that uses Snapshots, you might sooner or later run into a problem, where Xenserver tells you that there is no more free disk space on the storage, when in fact there is ample space left.

This happens because the space used by the snapshots is not actually freed up until the storage is rescanned.

Since I got tired of doing this manually every time the storage “ran full”, I found this little tip to have Xenserver scan its Storage every 30 seconds.

Unfortunately, the interval of 30 seconds can not be changed, and might lead to performance problem on larger installations.

However, so far I have seen no negative repercussions since having this activated.

So here is how to do it.

In your xenserver console, first run:  XE SR-LIST

This will show you alle the Storages configured on your host/pool.

Copy the UUID of the Storage you want to autoscan and then enter this command:

xe sr-param-set uuid=<UUID you copied above> other-config:auto-scan=true

That’s it. Now your problems with the ghost data should be solved.